Functional nanomaterial embedded lightweight polymer composites have drawn considerable attention across wide ranges of industrial applications. In addition to telecommunication and aerospace utilities, microwave absorbing materials must possess interesting properties that ensure excellent performance, from mechanical features to functionalities. Although conducting polymer composites containing magnetic nanofillers have been utilised widely, choosing the fillers from the library of nanoparticles and their effective dispersion inside the matrix may limit their usage in terms of performance, stability and durability. In order to overcome this bottleneck, herein we explored a facile bottom-up synthetic procedure to fabricate different shapes (spherical, cubic, cluster and flower, for example) and size-controlled Fe₃O₄ nanoparticles, and showed the effect of shape anisotropy and size on the above properties in a model polycarbonate (PC)/polyvinylidene difluoride (PVDF) blend with multiwalled carbon nanotubes as conducting nanofillers. The superior performance in terms of microwave attenuation and mechanical properties was reported for spherically shaped Fe₃O₄ nanomaterials. The excellent dispersibility of small-sized nanospheres was instrumental in the improved consolidated loss tangent values, attenuation constant, and impedance matching and skin depth, synergistically resulting in a shielding efficiency of −38 dB at 18 GHz.

中文翻译：

---

含软导电复合材料的铁氧体中的电磁屏蔽：尺寸和形状各向异性的关键作用

功能性纳米材料嵌入的轻质聚合物复合材料已在广泛的工业应用中引起了相当大的关注。除电信和航空航天业外，从机械特征到功能性，微波吸收材料还必须具有令人感兴趣的特性，以确保出色的性能。尽管包含磁性纳米填料的导电聚合物复合材料已得到广泛利用，但从纳米颗粒库中选择填料及其在基体内的有效分散可能会限制其在性能，稳定性和耐用性方面的用途。为了克服这一瓶颈，我们在这里探索了一种简单的自下而上的合成程序，以制造不同形状（例如球形，立方，簇和花状）和尺寸受控的Fe _3。O ₄纳米颗粒，并在模型聚碳酸酯（PC）/聚偏二氟乙烯（PVDF）与多壁碳纳米管作为导电纳米填料的混合物中显示出形状各向异性和尺寸对上述性能的影响。据报道球形Fe ₃ O ₄纳米材料在微波衰减和机械性能方面具有优异的性能。小尺寸纳米球的出色分散性有助于改善固结损耗角正切值，衰减常数，阻抗匹配和趋肤深度，从而在18 GHz时协同产生-38 dB的屏蔽效率。